Electric signaling system.



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K: A. HAWLTEYt ELECTRIC SHITBTLHIGV SYSTEM'.

AAPPLIOATION FILED TEIL?, 1908,

Patented Aug. 2"?, 191.2.

Amig .7

UNITED new;

' KENT A.. HAWLEY, lOF LGS ANGELES, CALIFORNIA, ASBIGNlEt 10 Submit AKMATI RAILWAY SIGNALCOMPANY, 0F LOS ANGELES, CALIFORNIA, A. CORCPQIRATION 01h".

ARIZONA.

WFiQE.

ELECTRIC BIGNALING SYSTEM.

Specification of Lettera iraient.

Patented Ang. 2'?, 191%..

- .Application filed February 7, 150e. Berta! to. tutti?.

To all ivwm it may concern.-

Be it kn'own that l,-,KENT A. HAwLnY, a citizen of the United States, residing at Los Angeles, in the county7 of Los Angeles and State' of California, have invented a new and useful Electric Signalin System, of which the following is a speci cation.

The main object of the present invention is to provide. means for indicating a defective condition or a variation of current in an electric circuit, particularly in an electric signal circuit. i,

A further object of the invention is to provide asigna] circuit wherein the normal signal is effected by the front contact o)- eration of the relay, and, therefore, by t e positive action of the electromagnet, in distinction to the relatively uncertain operation of gravity, or a spring, and at the same time any defective condition in `the signal circuit will be indicated or announced.

In the accompanying' drawings: Figure 1 is a diagram showing the application of the invention in connection with a signal, for example, an electric railway signal. Fig. il is a diagram showin,gr another arrangement of t-he signal circuit. Fig. 3 is a diagram showing a still further modification.

Referring to Fig. 1, 1 designates a circuit, and 2 a source of electric energy therein. In this circuit is included a resistance 8 and ina shunt 4 around or embracing this resistance is included a battery 5, for example, a secondary battery, and an indicator 12, which'may be a galvanomcter, electric lamp, bell, or other visual or audible indicating'device. 'Circuit .l-being in operative condi tion, the current liowing through the same fromthe battery 2 will cause adiierence of potential at the ends of resistance 3 represented by the product of the resistance and the current flowing therethrough and -the battery 5 is of just suflicienty strength to counterbalance this difference of potential so that normally there will be no current iiowing through the branch or second circuit 4, and the indicator 12 will be inoperative. Lack of operation of indicator 12, therefore, shows a normal condition in the operating' line 1. lf there is a variation of current or any failure of line 1 to operate by reason ot deficiency of battery therein, detective contacts, or break, etc., in the line, the difterence of potential at the ends of resistance B, due to the action of battery 2, will be decreased, or in case of a break, will be eliminated, so that the battery 5 will @anni an un 'opposed current through the branch circuit 4 thus operating the indicator 12 and showing' the variation or defective condition of the line,

1n applyingthe invention to a signaling system, for example a railway signal, the

circuit 1 is assumed to be a primary signal' clrcuit, closed by the armature 7 and from` contact 8 of a relay 9 in the main line circuit 10. |The circuit is assumed to be af normal safety circuit, the main-,line 1G being normally closed, and throufh the relay 9 and its armature? holding' tnehprimary signal circuit 1 closed. ln this circuit' l in this case is included -a safety signal 11, -tor example, agreen light', `which maintains operation as long as there is no variation in circuit 1 and the condition is that of safety. Under these conditions, the drop of potential in resistance 3 is normal andisbalanced' hy battery 5, and the battery fsends no current through the signal, or .bell 2, Which is included in the local shunt oftlietranch 4. Relay 9 has a back contact lfitetinected in a local circuit including tire bittt''y 1l,

for example, a red light 15, this being the danger signal for operation by.,tliclline.

'It is considered undesirable to depend, in a signal system, for operation of a relay on its back contact, but it will be noted that in this case there is in addition to the danger signal vat 15 a normal safety signal 11 controlled by the front contact and as long as the circuits are in operative condition the clear or safety signal is given at 11 by the the second circuit 4 announcing to thejoer-4 son in charge that the primary signa ing circuit is defective.

The signal lamp, or means 1l jmay 'ce used as the resistance around which the shunt et is connected, as shown in Fig. 2, the drop of potential in the lamp balancing the elec tromotive force of the battery 5. ln this also shown the use of a relay l? a signal means for indicating the 'defece condition 'o the circuit, said relay being Minded in the branch 4 and controlling a. local, or fourth, circuit 18 including a battery i9 and a 'nell 20 so that when the relay l?" becomes operative on unbalancing of conin the third circuit 4, the bell 2G in third circuit announces the defective indition. Such a relay may also be used connection with a special resistance 3 for iaintafring a diiierence of potential at 'tlie e branch circuit 4, as shown in will te understood that in the' applicau or' the invention to a railway signal, the' meegaan circuitI embracing said resistancesa ,source 30 of electromotive force third` 'circuit balancing the difference ci potentialat the ends of said resistance due to the normal Signal current flowing through said 're'sitance, and indicating means' in the thiricir- 35 2. A primary signal circuit including-a normally operated safety signal,r a main circuit and a relay therein having a front contact controlling said signal circuit7 and 40 having a back contact, a resistance in said signal circuit, a third circuit embracing said resistance, a source 'of electromotive force in said third circuit, jbalancinfr-.the difference of potential at vtliefends ci resistance due to the normalsignal current flowingithrough said resistance, indicating nieanslin said third circuit, and a (langer signal circuit connected tothe aforesaid .back

Contact of the main circuit.relaygandin- 50 cluding a danger signal. A Y. ,c in testimony whereof, I have hereunto set my hand at Los Angelica, California; this 31st day ci January 1968, l

In presence ef- Gnoiicn T., Hncni'inr, Fianna. Y' l" GRAHAM. y.' 'l

said 45 Kaur a n AWiLEjn 'l 

